Polymers comprising propylene and ethylene and/or other α-olefin copolymers are well known in the art, and are useful in a wide variety of applications such as films, nonwoven fabrics, molded articles, and in surface coating applications. Additionally, blends of these polymers with other polymers, such as hydrocarbon resins, have been described.
For example, U.S. Pat. Nos. 6,984,696 and 7,244,787 describe blends of propylene-based polymers with hydrocarbon resins in amounts from 5 to 30 wt %. The polymer blends are said to be useful in film, fiber, and nonwoven applications.
U.S. Patent Application Publication No. 2005/0107530 describes propylene/ethylene/diene terpolymers blended with hydrocarbon resins in amounts from 1 to 30 wt %.
U.S. Patent Application Publication No. 2006/0235159 describes blends of a first polymer component with a second polymer component, and optionally from 1 to 30 wt % hydrocarbon resin. The second polymer component is a copolymer of propylene and ethylene.
U.S. Patent Application Publication No. 2008/0182940 describes polymer blends comprising propylene/ethylene copolymers or terpolymers blended with a propylene thermoplastic and one or more additives, wherein the listed additives include hydrocarbon and functionalized hydrocarbon resins.
U.S. Patent Application Publication No. 2009/0258209 describes polymer blends comprising propylene/ethylene/diene terpolymers blended with a polyolefin and oil. The polymer blends are said to contain substantially no fillers and have haze values less than 65%.
One application for propylene copolymers is as a surface coating for plastic bottles, to improve customer appeal of such products by providing good optical properties, high definition, and “soft touch”. In order to be cost effective and maintain sufficient speed in filling lines, however, the coatings must also deliver an acceptably low coefficient of friction. Further, it is desirable that such coatings also exhibit the ability to retain small textural design details, sometimes referred to as “high definition”.
It has been surprisingly found that blending certain propylene/α-olefin copolymers with one or more hydrocarbon resins results in a surface coating composition that combines soft touch, acceptable haze properties, and high definition with a lowered coefficient of friction, thus improving upon previously known surface coating materials.